Automatic control device for variable width continuous casting mold

ABSTRACT

An automatic controlling device for continuous casting molds, comprising moving means linked, respectively, to the opposing short sides of the mold for continuous casting and an electric actuator means linked to said moving means. There is further provided a short side position setting means, a detector linked to said electric actuator means in order to produce a deviation signal based on the deviation between the setting signal and the short side position of the short side position setting means, and a sequence control means which controls the electric actuator means for the purpose of moving the right and left short sides alternatingly to the set position based on said deviation signal.

United States Patent 1191 1111 3,838,730 Nagaoka et al. 1 Oct. 1, 1974[54] AUTOMATIC CONTROL DEVICE FOR 3,439,736 4/1969 Strohschein et al.164/273 R VARIABLE WIDTH CONTINUOUS CASTING 3.583.473 6/1971 Strohscheinet a1. 164/273 R MOLD 3,710.845 l/l973 Burkhardt et a] 164/273 R v [75]Inventors: Toshiharu Nagaoka, Suita; FOREIGN PATENTS OR APPLICATIONSMasakazu Maruyama Kawagoe Germany M both of Japan Primary Examiner--R.Spencer Annear [73] Assigneez Concast AG, Zurich, Switzerland Attorney,Agent, or w w Kleeman [22 Filed: Aug. 13, 1973 l 1 AC 57 ABSTR T 21 A .2l 1 pp No 388 073 An automatic controlling device: for contmuous castingmolds, comprising moving means linked, respecl30] Foreign ApplicationPriority Data tively, to the opposing short sides of the mold for con-Aug. 14, 1972 Japan 47.30733 tinuous casting and an electric actuatormeans linked to said moving means. There is further provided 11 [521'US. Cl 164/154, 164/273 R, 164/4 short side position setting means, adetector linked to [51] Int. Cl 822d 11/02 said electric a t r means inOrder to produce a de- [58] Field of Search 164/4, 82, 154, 273 R,viation signal based on the deviation between the set- 1 4 2g3 M tingsignal and the short side position of the short side position settingmeans, and a sequence control means [5 6] References Cit d whichcontrols the electric actuator means for the pur- UNITED STATES PATENTSpose of moving the right and left short sides altemat- 3,292,216 12/1966Colombo 164/273 R mgly to Set based sald devlat'on 3,375,865 4/1968Boichenko ct a1. 164/283 M 1 Claim, 5 Drawing Figures l l A l to mlZlIIElI J 132m 16 d l 16t x i-'1 l m I F AUTOMATIC CONTROL DEVICE FORVARIABLE WIDTH CONTINUOUS CASTING MOLD BACKGROUND OF THE INVENTION Thepresent invention relates to a control device for automaticallycontrolling the size of a mold of continuous casting machines dependingon a desired molding size.

Conventional methods of changing the molding size in continuous castingmachine employs, as shown in FIG. 1, a mold composed of fixed long sides1 and short sides 2a and 2b which can slide therebetween, so that thedesired molding size can be obtained by adjusting the distance betweenthe short sides 2a and 2b. And so far, such adjustment has beenperformed by moving the short sides 2a and 2b by hand thereby measuringthe distance with a measurement scale. Hence, the adjustment was verytroublesome and a great deal of time was needed, accompanied bydifficulties, if it is intended to obtain an accuracy of even about 0.5percent. In addition, the molten metal poured tends to be cooled andshrinks as it descends down the mold; and hence taking this intoconsideration, the mold had to be tapered. But with the conventionalmanual adjustment, control of the tapering was very difficult andfurthermore, a lot of clumsy operation was inevitable for centering themold with the drawer means, and as a whole, the controlling operationwas very clumsy and difficult.

OBJECT OF THE INVENTION Therefore, an object of this invention is toprovide .a control device which is capable of automatically controllingthe distance between the short sides of the mold as well asautomatically defining the centering, thereby eliminating theabovementioned drawbacks.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will becomeapparent when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings wherein:

FIG. 1 is a perspective view of the mold;

FIG. 2 showsthe actuating means for actuating the short sides of themold and a circuit diagram of an automatic control;

FIG. 3 illustrates the order by which the short sides of the mold move;

FIG. 4 is a circuit diagram of the sequence logic circuit of theautomatic control unit; and

FIG. 5 illustrates the operation of the logic circuit of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the invention isillustrated below with reference to the accompanying drawings. First,illustrating the outline of this invention, the short sides and 2b haveat their upper and lower sides a moving means and a position detector.The moving device is actuated by the output signal of the detector, inorder to move the short sides 2a and 2b sequentially as shown in FIG. 3thereby giving a determined distance and tapering to said short sidesand then .to move the central position of the distance between the shortedges by a determined amount.

Referring now to FIG. 3, let us suppose that; l. the short sides 2a and2b have initially the lower end distance 1., being tapered. and are thenmoved so that the lower end distance is I and the upper end distance acquires the set position I Al; 2. a starting push button is pushed andthe upper end of the short side 2a restores to the perpendicularlystanding position; 3. and then the short side 2b restores to itsperpendicularly standing position; 4. if both short sides are electedper-, pendicularly, the short side 20 is moved in parallel to theposition where the lower end distance I is acquired; 5. and then theshort side 2b moves in parallel to the position where the distance I isacquired; .6. then only the upper end of the short side 2a is moved tothe position equivalent to the set distance 1+ Alto acquire a determinedtapering;

7. and then the short side 2b is moved in the same way so that the moldacquires the determined size.

The above-mentioned operation is carried out automatically by thesequence control device. But, 8) in order to move the center of thedistance between the short sides by a, the distance be moved by a in theorder of the short side 2a and then the short side 212 by using part ofthe operation of said sequence control device after the above-mentionedoperation has been completed.

FIG. 2 shows the construction and circuit diagram of this invention.Automatic controlling mechanism of the 7 short sides 2a and 2b are thesame and operate alternatingly to move the short sides to the setposition as will be mentioned later; hence only one of the controllingmechanisms is illustrated here. But where it is intended to indicate theright or left side mechanism, a symbol a or b will be attached.

, To the upper and lower ends of the short side 2a are attached bymeansof a pin an end .of the lead screws 3 and 4 which have been heldhorizontally for moving purposes, and the male screw members are linkedrespectively to the reduction devices 5, 6 having equal reduction ratio.And both reduction devices 5, 6 are linked together by theelectromagnetic clutch 7a. The input shaft of the reduction device 5 islinked to the reversible motor 9a through the reduction device 8, and islinked to the rotor of the detector Ila composed of a controltransformer through the reduction device 10. Hence the upper position ofthe short side 2a is determined by the number of revolutions of themotor 9a. And the reduction ratio of the reduction device 10 is sodetermined that the rotor of the detector 11a produces an angulardisplacement within 180 deg. for the maximum practical revolution of themotor 9a, i.e., for the maximum moving size of the short side 2a, forthepurpose of indicating the position of the short side 2a in terms of therotor angular position within 180 of the detector lla.

The digital setting device 12 for setting the distance across the shortsides 2a and 2b comprises a setting device for providing the lower enddistance I which will be changed, a setting device 121' for providingthe upper distance I Al, and a setting device 12F for providing thelower end distance I prior to the change effected, and the digital setvalues of each setting device are converted into analog signals throughthe digital-toanalog converter incorporated and are fed to the zeropointshifter 13 through the changing contacts 16d, l6t,

16f, and common line 18.

The zero-point shifter 13 is a device to bring the central position ofthe distance between the short sides 2a and 2b into alignment with thecentral position of the drawer next to the mold, and has been soconstituted as to rotate the rotors of the control differentialgenerators 13a, 13b belonging to the short sides 2a, 2b in the reversedirection to any angular position by means of a shift lever. The statorcoils of the control differential generators 13a, 13b are connected tothe common line 18, and the rotor coils are connected, respectively, tothe stator coils of the detectors 11a and 11b through the contacts 17aor 17b.

The sequence control unit 19 possesses the relay amplifier 14 and thecontrol unit 15 in FIG. 2, these have been expressed as 14a, 14b, 15a,15b, separately on the right and on the left, for convenience. But theseneed not be provided separately on the right and on the left; a singlerelay amplifier 14 and a control unit 15 may be used commonly for theright and left short sides 2a and 2b. The relay amplifier 14a possessesa highspeed relay amplifier 14ah and a low-speed relay amplifier 14a].Both relay amplifiers 14ah and 14a] receive the rotor output of thedetector 11a. When said output is large, the relay amplifer l4ahoperates, and when said output is small, the relay amplifier 14a]operates to provide signals to the control unit 15a. The control unit15a, depending on these signals, actuates the motor 9a at a high or lowspeed in the direction along which the rotor output of the detector 11abecomes 0, and controls to make or break the electromagnetic clutch 7aas well.

The contacts 16d, 16!, and 16f open or close in a sequential manner dueto the logic circuit mentioned later, and the control device of thisinvention works as mentioned below.

1. Let it be supposed that the short sides 2a and 2b are in taperedstate as shown in FIG. 3, l), with the contacts 16d, l6t, and 16f open,and the contact 17a closed, and the contact 17b open. Theelectromagnetic clutches 7a, 7b are all open, and the zero-point shifter13 is in position.

2. Under such condition, if a starter push button is pushed, the startersignal S shown in FIG. 4 produces a signal x to close the contact 16f,and a setting signal (l /2) produced by the setting device 12F entersinto the detector lla through the common line 18, zeropoint shifter 13,and the contact 17a. The rotor position of the detector lla assumes anangular position corresponding to the upper position of the short side2a prior to its change; hence a signal So representing onehalf of thedifference in clearance between the upper end and the lower end of theshort side 2a will be developed on the rotor of the detector 11a andenters into the relay amplifier 14a. When the difference in saidclearance is too great, the relay amplifier l4ah operates so that thecontrol unit a actuates the motor 9a at a high speed in the directionalong which the signal 80 becomes small. When said difference is small,the relay amplifier l4al operates to actuate the motor 90 at a lowspeed. In this case, since the electromagnetic clutch 7a is being openedthe lower end of the short side 20 does not move and only the upper endmoves inward so that the short side 2a is erected perpendicularly. Andas the difference in said clearance is minimized and the signal So isreduced to a definite value, the output of the relay amplifier l4al isterminated and the motor 9a is stopped after some idling, so that theshort side 2a is stopped at a position erected perpendicularly (FIG. 3,2)). And as the signal So acquires 0, the completion signal PR isproduced to change the opening-closing state of the contact 17a and 17b.

3. As the contact 17b is closed by the above changing, the settingsignal of the setting device 12F enters to the detector 11b, so that themotor 9b is started and the short side 2b is erected perpendicularly asmentioned above (FIG. 3, 3)). As the output signal So of the detector11b acquires 0, the completion signal PL1 is produced.

4. Said completion signal PLl enters to the logic circuit shown in FIG.4, and causes the signal x to assume 0 so that the contact 16f isopened, and causes the production of signal y so that the contact 16d isclosed. At this time, the completion signal PLl changes theopening-closing state of the contacts and 17b again, so that theelectromagnetic clutches 7a, 7b are closed.

In this way, the set signal (N2) of the setting device 12D enters to thestator of the detector 11a. At this time, since the rotor of thedetector 11a is in an angular position representing 1 /2, a signal S1representing (I l )/2 will be developed on the rotor, causing the motor9a to start in the same way as in (2) above. At this moment theelectromagnetic clutch 7a is being closed, and hence the short side 2amaintaining a perpendicular condition moves to the position of distanceI at which the signal S1 acquires 0 (see FIG. 3, 4)). At the completionsignal PR is developed again to change the opening-closing state of thecontacts 17a and 17b.

5. As the contact 17b is closed by this change, said setting signal ofthe setting device 12D enters to the detector 11b, and the short side 2bmaintaining a perpendicular condition moves to the position of distanceI in the same way as mentioned in (4) above (FIGS. 3, 5). When themovement is finished, the completion signal PL2 is produced again tochange the contacts 17a and 17b, and renders the electromagneticclutches 7a and 7b to be opened. The completion signal PL2 also rendersthe signal y to acquire 0 causing the contact 16d to open, and producesa signal 2 to close the contact 16!, as shown in FIG. 4.

6. In this way, the setting signal (representing (I Al)/2) of thesetting device 12T enters to the stator of the detector 11a. At thismoment, since the rotor of the detector 11a is at an angular positioncorresponding to l/2, a signal S2 to represent Al/2 will be developed onthe rotor. And since the electromagnetic clutch 7a is being opened, theupper end only of the short side 2a will move to the position of l Al.When the movement is finished, the completion signal PR is producedagain and the opening-closing state of the contacts 17a and 17b arechanged.

7. As the contact 17b is closed by this change, said set signal of thesetting device 12T enters to the detector 11b and moves only the upperend of the short side 2b to the position of l AI the same way asmentioned above. When the movement is finished, the completion signalPL3 is produced again so that the signal z acquires 0 causing thecontact 16t to open, and thus changes the opening-closing state of thecontact 17a and 17b. In this way, the contacts and the electromagneticclutch return to their initial condition.

As mentioned in the foregoing, the contacts 17a and 17b are changedopened and closed for every production of the completion signals PR, PL.The comple- ..tion signal PL further causes the production of thesignals x. y. z, in serial mode as well as the production of thestarting signal S; for this reason the sequence control unit 19 isequipped with the logic circuit as shown in FIG. 4.

Referring to FIG. 4, numerals 21, 22, 23, 24, 29 and 30 represent ANDcircuits; 25, 26, 27, and 28 represent OR circuits; 31, 32 and 33represent NOT circuits; and Tsl and Ts2 denote delay circuits. In FIG.4, if a starting signal S is fed with the signals x, y, and z being 0(contacts 16d, 16:, and 16f being open), the AND circuits 21 produce asignal x (contact 16f is closed) since the outputs of NOT circuits arel, and this state is maintained by OR circuit 25 (FIG. 5, c).

Then when the first completion signal PLl is fed, it (first completionsignal) is carried through the OR circuit 26 to the AND circuit 22. Atthis moment, since the outputs of the delay circuits Tsl and Ts2 arestill 0, the outputs of AND circuits 29, 30 will be 0. Hence the outputof AND circuit 24 is 0, and the output of NOT circuit 33 is 1.Therefore, the AND circuit 22 produces signal y (contact 16d is closed)and this state is maintained by the OR circuit 26, and feeds a 0 signalto the AND circuit 21 through the NOT circuit 31 rendering the signal 1:to be 0 (contact l6fis open) (FIG. 5,d).

The signal y also enters to the delay circuit Tsl. But since thedelaying time t, of the delay circuit Tsl has been set to be greaterthan the duration t of the completion signal PLl, the delay circuit Tsldoes not produce an output as far as the completion signal NJ is presentand produces an output of 1 after the completion signal PLl has beenextinguished (FIG. 5, f).

Then when the completion signal PL2 is fed again, the output of thedelay circuit Tsl will have already been 1; hence the output of the ANDcircuit 29 is 1. At this moment, since the output of the delay circuitTs2 is still 0, the output of the AND circuit 30 will be 0, and theoutput of the NOT circuit 33 will be 1 so that the AND circuit 23produces an output z (contact 16! is open) (FIG. 5, e) and this state ismaintained by the OR circuit 27, and in addition, the signal Z feeds 0signal to the AND circuit 22 through the NOT circuit 32 to cause thesignal y to be 0 (contact 16d is open).

The signal z is also fed to the delay circuit Ts2. But since thedelaying time of the delay circuit Ts2 has been set to be greater thanthe duration'r of the completion signal PL2 as in the case of the delaycircuit Tsl, the delay circuit Ts2 does not produce an output as far asthe completion signal PL2 is present but produces an output 1 after thecompletion signal PL2 has been extinguished (FIG. 5, g).

Then if the completion signal PL3 has entered, the output of the delaycircuit Ts2 will have already been I, and the output of the AND circuit30 will acquire l and at the same time, the output of the AND circuit 24will also acquire 1, so that the signal z is turned to 0 due to the 0output of the NOT circuit 33 (contact l6t is open) (FIG. 5, e). And dueto the OR circuit 28, the output of the NOT circuit 33 is maintained at0 so far as the completion signal PL3 is present, and hence the signal yis maintained at 0 as well. The logic circuit, in this way, returns toits initial state.

Next in order to bring the central position of the distance between theshort sides 2a and 2b into alignment 1 with the central position of thedrawing device, the

upper and lower ends of the short sides 2a and 2b mentioned above, andthe following control he carried based on said deviation signal.

out. In this case, no sequential control by means of the logic circuitis performed, which was effected in the foregoing.

First, the zero-point shifter 13 is turned by means of a shift lever toset, based on the graduation, the amount a by which the central positionof the distance between the short sides 2a, 2b moves. Then, for example,the switch connected in parallel with the contact 16! is closed, and thestarter push button is pushed with the electromagnetic clutches 7a, 7bclosed. Since the contact 17a has already been closed and the contact17b has been opened due to the completion signal PL3, a signal (1 +131)/2+a will be put into the stator of the detector 11a. On the other hand,since the upper end of the short side 2b has already been adjusted to(1+A1 )/2 on account of the adjustment effected up to the previous time,a signal of the magnitude of a will appear on the rotor of the detector11a. This signal a works equal to the signal So mentioned in (1) above,and causes the motor 9a to start. But as the clutch 7a has been closed,the short side moves by a in parallel and stops its movement. Thecompletion signal PR is then produced and changes the contacts 17a, 17b.

At this moment, a signal of a magnitude equal to (l+Al)/2 0 is producedby the control differential generator 13b and enters to the stator ofthe detector 11b; the motor 9b is then started causing the short side 2bto move by the amount -a, and is stopped. In this way, the center of thedistance between the short sides 2a and 2b is moved by the amount a(FIG. 3, 8)).

As mentioned above, according to this invention, the distance betweenthe short sides and the taper can be adjusted automatically only besetting the distance between the short sides 2a and 2b by means of thesetting device 12, and in addition the central position of the mold isbrought automatically into alignment with the central position of thedrawing device by meansof the zero-point shifter. In this way, theadjustment of the mold size is performed quickly and accurately.Furthermore, the left and right short sides are controlled alternatinglyand automatically by means of a common setting device and a controlunit, and the upper and the lower ends of the short sides are separatelyor simultaneously moved for the purpose of defining any distance betweenthe short sides and tapered angle. In this way, according to thisinvention the moving means and the control units have simpleconstruction.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto, but may be otherwise variously embodied and practicedwithin the scope of the following; claims. ACCORD- INGLY,

What we claim is:

1. An automatic controlling device for continuous casting molds,comprising moving means linked, re-

spectively, to the opposing short sides of the mold for continuouscasting, an electric actuator means linked to said moving means, a shortside position setting means, a detector linked to said electric actuatormeans in order to produce a deviation signal based on the deviationbetween the setting signal and the short side position of the short sideposition setting means, and a sequence control means which controls theelectric actuator means for the purpose of moving the right and leftshort sides alternat ingly to the set position

1. An automatic controlling device for continuous casting molds,comprising moving means linked, respectively, to the opposing shortsides of the mold for continuous casting, an electric actuator meanslinked to said moving means, a short side position setting means, adetector linked to said electric actuator means in order to produce adeviation signal based on the deviation between the setting signal andthe short side position of the short side position setting means, and asequence control means which controls the electric actuator means forthe purpose of moving the right and left short sides alternatingly tothe set position based on said deviation signal.